CHIMORE, Bolivia — It was 11 p.m., and the village market at Isinota teemed like a beehive. At dozens of lantern-lit tables, each equipped with a set of scales, hundreds of peasant farmers were selling softball-sized wads of cocaine paste.
Approaching quietly from the surrounding darkness was an eight-man team of Leopards, the Bolivian anti-narcotics police, accompanied by a special agent of the U.S. Drug Enforcement Administration. Shotgun blasts, aimed at the open-air market's metal roof, announced the raid.
Buyers and sellers bolted, upsetting tables in their haste, abandoning cocaine and cash. The Leopards, too few to give chase, brought in a truck and began gathering up the scattered money and tissue-covered balls of paste.
But soon hundreds of angry peasants swarmed back to the market. They hurled rocks and sticks of dynamite, which exploded dangerously close, according to police Maj. Primo Pena.
'Get Out Fast'
"I fired shots in the air while the men loaded drugs," Pena said in an interview. "Then we decided to get out of there fast. A lot of drugs were left on the ground."
The Leopards managed to seize 638 pounds of the paste, which is a crude form of cocaine into which the powder and "rock" or "crack" sold on American streets is refined.
The mid-April raid was part of a changing scene in the Chapare region of central Bolivia, where small jungle plots produce most of the coca leaves and cocaine paste that make this South American country a major international drug source. Other changes:
-- In the last year, the United States has quietly but substantially expanded the number of American advisers and trainers working with the Leopards.
-- With the increased aid, the Leopards have improved their competence and--at least when Americans are present--their resistance to corruption.
-- The joint effort has yielded significantly better results in anti-drug operations, such as the Isinota raid, causing heavy losses for traffickers and peasant producers.
-- In response, traffickers have begun to operate more cautiously and peasants are showing new signs of angry frustration, such as the mob attack at Isinota.
Overall, the changes are notable if not dramatic. They will be useful to the Reagan Administration in arguing against congressional reductions in U.S. economic aid to this impoverished nation because of drug trafficking.
But it also seems clear that U.S. anti-drug aid to Bolivia is still inadequate, that corruption among Leopard officers is still a major problem and that the cocaine traffic is still going strong.
Bolivian law permits the production of coca leaf, traditionally chewed by Indians as a mild stimulant. But the bulk of the country's coca harvest is converted into cocaine for export.
The Leopards, trained and equipped by the United States, began anti-drug operations in 1985, but cocaine traffic continued to flourish.
Last May, a 14-man U.S. Army team specializing in jungle operations came here to start retraining the Leopards in conditioning and basic tactics. There is still an Army team here at Chimore, the Leopards' base camp in the Chapare, and a similar Army team began giving advanced training at a site outside the Chapare in February.
Police More Skilled
U.S. officials credit the policemen with responding well to the training. They have become more skilled at moving through the jungle, sneaking up on cocaine paste laboratories and occupying them militarily with helicopter support, the Americans say.
In June, yet another U.S. Army team will start a special series of courses for Leopard officers. Officers were supposed to take basic training along with the enlisted policemen, but most have been unwilling to go through the grueling course alongside men of inferior rank.
The authorized strength of the Leopards is 50 officers and 500 enlisted men. Most are stationed in Chimore or in the Chapare, where they operate with DEA advisers.
About a year ago there were only three or four DEA agents in the Chapare. Now there are up to 10, including U.S.-based agents flown down for temporary duty.
In addition, two U.S. Border Patrol agents are on temporary assignment advising Leopards at a checkpoint on the highway into the Chapare from the city of Cochabamba. They search vehicles for kerosene, lime, sulfuric acid and "precursor" materials used to process coca leaves into paste.
An unofficial but important task of the DEA and Border Patrol agents is to keep the Leopards honest. With Americans looking over their shoulders, Bolivian officers are less prone to accept bribes from drug traffickers. But the Americans cannot be everywhere, and corruption remains serious, according to knowledgeable Americans and Bolivians.
"There is corruption in Bolivia, that is certain," acknowledged Ernesto Machicao, a high official in the Interior Ministry. He expressed doubt that the enforcement effort will have much impact on the flow of cocaine from Bolivia as long as bribes keep major traffickers free.